Machine tool



Nov, 27, 1951 w. L. BENNINGHOFF ETAL l 2,576,095

MACHINE TooL Filed Feb. 26, 1945 1:5 Sheets-sheet 1 M/ NNTORS BY @iF/em ATroRNr-:Y

Illl V4Nov. 27, 1'951l iW. L. BENNINGHOFF ETAL vMACHINE! TOOL 13 Sheets-Sheet 2 Filed Feb. 2e, 1945 loa ,0'7 no INVENToRs n BY ef-7 7&4@ ATTORNEY NOV 27 1951 w. l.. BENNINGHOFF ETAL 2,576,095

MACHINE TOOL 13 Sheets-Sheet 5 Filed Feb. 26l 1945 S R O T. N E V m ATTORNEY N0V- 27, 1951 w. l.. BENNINGHOFF ET AL 2,576,095

MACHINE TOOL Filed Feb. 26, 1945 15 Sheets-Sheet 4 a/IQ/ENTORS M f Y 7@ BY 'f5/MM5 ATTORN EY w. L. BENNINGHOFF ET AL 2,576,095

MACHINE 'rooL 15 Sheets-Sheet 5 Nov. 27, 1951 Filed Feb. 2e, 1945 Nv. 27, 1951 w. L, BENNINGHOFF Erm. 2,576,095

MACHINE TooL 13 Sheets-Sheet 6 Filed Feb. 26, 1945 INVENToRs mai/ ,F

BY fw ATTORNEY Nov.27, 1951 W.L..BENN1NGHOFF ETAL 2,576,095

MACHINE TOOL Filed Feb. 2e, 1945 13 sheets-sheep 7 'INVENTOR`S- MW m ATTORNEY NOV- 27, 1951 l wfL. BYENNINGHOFF Erm.

MACHINE TOOL gt3 sheetssheet s jaa.

Filed Feb. 26, l1945 Y |NvENToR ,Xm /59 BW F l ATTORNEY 6T.. ZZ

4 Nov. 27, 1951 MACHINE TOOL w. L.. BENNINGHOFF ETAL 2,576,095

15 Sheets-Sheet 9 Filed Feb. 26, `1945 F1 7. EE

, 2 ATTORNEY Nov. 27, 1951 Filed Feb. 26, 1945 WfL. BENNINGHOFF ET AL MACHINE TOOL 13 Sheets-Sheet 11 INVENITORS` WKHW'? I F /g M BY W ATTORNEY NOV- 27, 1951 w. l.. BENNINGHor-'F E-rAL 2,576,095

. MACHINE TOOL 13 ,sheetfsheet 12 Filed Feb. 26, 1945 .mum

| l llli N0V- 27, 1951 w. l.. BENNINGHOFF vE-ru. 2,576,095

MACHINE TOOL lFilled Feb. 2e,V 1945 INVENTORS BY QM 4 ATroRNEY Patented' N0v.27,19s1 2,576,095

UNITED STATES PATENTOFFICE 22 Claims. 1

The inventionrelates:` tomachine tools and particularly to tools for cutting screw threads', `i1"1-A cludingA taper: threads.` i The `invention .is Iapplicable to the cutting of both exter-iorand interior threads, but for purposes of explanation 5 `a rotary spindle threadcutting apparatusof thelit `will 1be-shown las Aembodied `in; Eapparatus decharacter above indicated havingimpr'oved means i signed for the cutting ofr external threads'. r by which 'theapparatuscanlconveniently be ad;A

It is a principal object of the invention to justed to cut threads of various tapers.- i provide 4a machines-for cuttingscrew threads that A further `cbjectfof theinvention is AtonV provide is `largelyautomatic in` operation andA capable of `threact-cuitiiig*r apparatus ofthe receding ,chaser` performing rapid, yet uniform and reliable, op-f typehaving improved -means forlvary'ing the dierationsLupon work pieces fedV to it in succesametersof the thread cut.` sion, with resultantlargecapacity for the turn- The'ihventinha-sffoanotherofitslobjeetsfthe A ing'outofwork of high quality. provisioi1,`ina metal-lworkingmachine compris;k The invention has foranotherrof its `objects ii'ring a cutter'lnechaiiisingja Workehlding mecha`` the provisionin `a thread-cutting machine of the i nisni'and a feed'cairiage frsupporting one of 1 typehaving thread-forming apparatus with colsaid mechanisms, of means for moving the car" lapsible chasers, a Work chuckgvmeans for effectria'ge comprisinga "drive cain," variable speed ngrelative rotation of therfsaidv apparatus and ge"ar""'g`"fo`r` moving tl'ecam-"to` effect 'carriage chuckand means for effecting their relative axial myfeed" movement *during the cutting operation of-VM movement, rst toward and then away irorneach` the machine, and uid pressure operatedjfirieans other, of means operating automatically in sucforrzidi/ing` the cam in the reverselfdirect-ionincession toclose the chuck upon a Work piece predependently` of said gearing to' effect a rapid re-i sentedYto-the chasers, effect to slowA forward feed turn movement'of thecarriage. of the workpiece in 4relationstothe chasers, a 25 Another `object,ofthe' invention is to providea rapid retraction of the work piece from the machineof the character referred tointhe last` chasers and opening of the chuckto release the Y stated object in which the cutter mechanism is work piece. vadapted to form'screw'threads `and in which the f Affurther object of theinvention is to provide a feed" cam is adjustable `to" coinpensate for zerrors machine for attaining the above stated objects of leadthat `might 'oth'ewiseoceur in the thread having control and actuating devices energized by cut by the machine. fluid pressure with resultant attainment of high Another object of the invention-is toprovidea speed movements `for various parts of the mecha? machine such as referredfto in the-lastbut' `one nism preparatory to and following"` `the actual of the foregoing objects in`which the cuttermech-f-v tlieadecuttng Operation, With'iesfltant attain` 35 anisnris "adaptedA tQ ^scr`ew"th`read^s` andi in ment of a short over-al1 Atime of th operating which theconnectionbetweenthe feed carriage`` cycle.` Y andl itsactuating carril isfad-justable to provide- Another object of the invention is to provide for cutting threads of different lengths whilefper-l thread-cutting apparatus of the receding-chaser mittingsupport fcnthe workv relatively close to type. in which the chasers are movably mounted 40 tliecutters. i in one end of a hollow rotaryspindle and are The invention "hasffor another of its objects" actuated by means supported from interior sur'` theprovision'inA a metal-working machine comfaces of the spindle while the spindle itselfiis prising-a thread-'cutting niechanisml a {work-j rotatablysumnorted` by exterior bearings one of holding mechanism andafeed carriagefo 'sup-A which is close to the chasers for Afirm support portingoneofsaidmechanisms,` ffe'edmechathereof. j nisrn` ,forthe carriage comprising ia drive cani,-

The invention has for another object the pro?i a1id""ea"cii1ydisgagieable-connecting jmea-nsbvisionof thread-cutting apparatus `ofthe reced'- tween the camV devices and the carriage `to pejr= l ing' and collapsing chase type in which *the mit-thalatt tothe-movedlawayfromltlie chasers are mounted on a rotary spindle and have thread-cutting mechanism and afford "access their-actuating mechanism constructed and ar'- thrt* g ranged within the spindle'sc'` thatlit is possible A further object of-fthe inventinis tiret-provi? both to secure great compactness and dust-proof siofnyin a threadseuttingiiiachine in which work enclosure' for the mechanism and at the saine tdbethreied" is held by a `fluida`ctilated 'chuckif time to provide adequate bearing 'supportfoi-the supported lav-'a` feed'carri"ge and the-peratioiilf* 1 A 2;. n n spindlerelatively close to the chasers so asf-to attainf'rmnessofWsupportfor the chasers and thfe-`advantages resuitmgfroin such support.`

Another objectof'itheinvention is to-provide-- operation, of improved means for manually dis-V connecting the automatic re-setting means, effecting collapse of the cutters, re-setting the cutters and restoring the operation of the automatic re-setting means.

The invention has various other objects, more or less incidental or ancillary to those above 4 of the thread cut, Fig. 13 showing the cam de-i vice set for cutting a taper thread, while Fig. 14 shows it set for the cutting of a straight thread. Fig. is an enlarged reproduction of the middle part of Fig. 8 to better show the construction of cam mechanism employed for causing gradualretraction ofthe cutters- Fig. 16 is al view'similar. to Fig. 15 but showing the movable parts in the positions occupied after some retraction of the cutters has been effected.

Fig. 17 is a longitudinal section on the line n n of Fig. 16.

noted, which will appear in' the'following description of an exemplary embodiment. of our improvements shown inf the accompanying drawings.;y l

with auof the Vvarious,fetj'eets m view the invention consists in l features lof construction andcombination of parts to/be explained in the following detailed description having reference tothe accompanying Vdrawingsand will be particulally pointed out in the appended claims.

In the drawings, Y

Fig. 1 is a front elevation of a machine embodying the invention, it being designed to cut external taper threads on pipes, rods and the like.

Fig. 2 is an enlarged elevation of the left end of the machine with a portion thereof broken away to permit of the large scale showing and with one of the cover plates of the machine removed to better show a portion of its drive gearing. f

Fig. 3 is a fragmentary section taken on 'the line 3;-3 of Fig. 2 showing in elevationa portion of Athe power transmitting gearing of the machine.

Fig. 4 is an enlarged plan view of the machine with a middle portion thereof broken away, with the -top part of the machinecasing cut. away to reveall the horizontally disposed'v spindle of the thread-forming apparatus,` the gearing for driving the sameand the gearing by which the said spindle is operatively connected todrive the carriage feed mechani'sin which is shown at the right end of the figure where the machine casing is partially broken away. Y

Fig. 5 is a fragmentary vertical section on the lineV 5--5'of Fig. 4 showing means for adjustingV the carriage-actuating cam. l

Fig. 6 is a developmental sectional view taken Y on the broken line 6-6 of Fig. 2 and showing the major part of the drive vgearing aty the left end of the machine.

7 is an enlarged longitudinal sectional view of the thread-forming apparatus, thersection being taken lon the line 1-1 of Fig. 9.

Fig. 8 is a horizontal axial section showing the mainparts of the thread-forming mechanism shown in Fig. '7. l

Fig. 9 is a vertical transverse section on the line 9-9 of Fig. 7. Y

Fig.V 10 isa transverse section on the line Ill-l0 of Fig. 7. c

Fig. 11VV is a transverse section on the line lI-ll Vof Fig.8.

Fig. 12 is a fragmentary longitudinal section on theline |2-l2 ofFig. 11. I

Figs. Y13 and A14. are fragmentary showing the adjustable cam device of the threadcutting. .mechanism which @,ermmes then taper.

detail views Fig. 18 is .a transverse section on Ythe line I8-l8 of Fig. 16.

Fig. 19 is an'enlarged fragmentary plan View of'aV portion of the machine carriage and the Vworl: chuck or gripper mechanism with some of Fig. 23 is anwenlarged fragmentary vertical."

section taken on the line 23-23 of Fig. Y4. and.,

illustrating a portion of the carriage feed mechanism..Y Y, Fig. 24 isV an enlarged fragmentary transverse i section ofthe machine taken on the line .2d-24' ofv Fig. 4.

Fig. 25 is an enlarged fragmentary section taken on the broken line 25g-25 of Fig. 4.

Fig. 26 is an enlarged rear elevation of aportion of the machinewith a considerable part thereof broken away to permit larger scale illustration of Vfluid pressurecontrol-and actuating devices of the machine.Y Y -Y i Fig. 27 is an enlarged detail 'view of one of the valves of the machine andthe cam-V means foractuatingit. Y I fY-W- Fig. 28 is a largev scale front elevation of por- I tions of the machine, Awith some parts shown in sectionyto illustrate vthe automatic devices for v' rer-setting the thread-forming chasers following their collapse at the end of thethread-cutting operation, together with manual devices for dish connecting the automatic re-setting means and effecting manual 'collapse andre-setting of the cutters.

Fig. 29 is a fragmentary Vvertical section showing the Ladjustable connection betweenv the machine carriage and the cam feed device with the said Yconnection broken'to permit independent movement'ofthe carriage. Y

Figs.' 30V and 31 are fragmentary detail'viewsff, of the manual collapse and re-setting devices showingjthem in positions of operation different frirfrtheV positions shown in Fig. 28;

Fig1f32 is ar diagrammatic view'of the fluidpres'sure-actuated devices Yof the; machine-"to- .f gether'with their control devices.

Figsj and 34 are fragmentary side elevations showing one ofthe pilot valves and its actuating cam in different positions in the 'cycle of operations...V Speakinggenerally, the machine shown in the drawings f comprises a .main"`1ldor'supported frame'orfcasing structure designated as an en` tirety byV the numeral I..-'Ihisframe has at its a rightnend a boltedfon extension la. V-At the left or head end ofthe machinaasview'ed from the front, is disposed thread-cuttingapparatus with@I mangiar.;@martelli effecting resiedivaeed lattacca 512 cdllapsing movements `of the chasers; kthis apparatus being designated `as an entirety `by the numeral 2. 3 designates `as `an entirety `a Work carriage slidably mounted on ways on the frame I;` and 4 designates as an entirety `a Work-holding gripper or chuck mechanism for which thecarr-iage structure serves as a supporting frame.

A combined fluid and gear operated feed mechspindle of the thread-cutting vapparatus by `a variable speed drive mechanism designated as an entirety by 1, While thenumeral 8 designates as an entirety a variable speed gear drive `'mechanism between the said spindle and the carriage feed mechanism 5.

I'he machine further comprises a system of fluid actuated devices for operating and coordi hating the movements of various parts and de vices of the machine, and this system is designated as an entirety by the numeral 9 (Fig. 26). The machine is provided also with -a manually operable mechanism, designated as an entirety by the numeral Iffor collapsing and re-setting the chasers cf the thread-cutting apparatus independently of the automatic control of the machine.

The above noted main portions of the machine will now be described in detail.

The thread-cutting apparatus As has been stated, the machine shown by way of example in the application drawings is designed to form external screw threads and for brevity and `convenience the thread-forming apparatus -2 will be referred to as the die, with the understanding that the `latter term is not used in a limiting sense.

The die mechanism has a tool body'in the form of a hollow spindle which comprises a main part or body II rotatably mounted at its right and left ends in roller bearings I2 `and I3, respece tively. A ring nut I4 is provided to afford adjustment for both of the bearings. Keyedon spindle body II are driven and driving `gears I and I E, respectively, which are secured against axial movement by a spacer sleeve Il and ring nut I8. In addition to the spindle body Il, the tool body or spindle comprises a head I9 secured to body II by screws 2d. The spindle body II is formed at its front end with four forward extensions or iin-gers ia to which head it is rigidly secured by the screws 2&3. The spaces between adjacent ngers thus provide four openings through the side wall of the spindle.

The head I3 is `formed with a plurality `of radial slots in each of which is slidably mounted a chaser block 2i which carries at its inner end a chaser 22 secured by Wedge block 23. `The blocks 2I are slidably secured in their slotstby an annular plate or ring 24 which is secured byfscrews (not shown) to the headIB. i u

The chaser blocks and their mounting in the head of the tool body are of well known construction such as is shown in the UnitedStates patent to Benningho, No. 2,054,028 (Fig. 13), each block being provided with a` pair of coi-l springs which urge the block radially outward in its guide slot. As the present invention is not concerned with these details "they `are not fully sho'wn'fand need not befurther-describedel The'die' is provided with a chaser-actuating slide which'i's designated `as an entirety by the numeral 25 and which will generally be referred tclin the following description as the outer slide.

1^ This-outer slide 25 comprises a tubular body 26 slidably mounted in the spindle body II and a i headstru'cture -2'I `comprising a nxedtmember 28 of annular iianged form and an annularanged member `29 having screw threaded engagement` Y with the member 28 to permit axial adjustmentof said member 29. The head member 28 is formed with four apertures 28d through which extend the fingers "I Ia of the spindle body II and at points radially inside of these fingers member .2s is rigidly secured by screws 3U to the tubu- The ngers IIa, by`

lar member 2 5 of the slide. theirengagement with apertures 23a key the slide structure 25 against rotation relative to spindle i body II. A plurality of set screws 3imo`unted in head member 29 to 'engage member 2B serve to hold themember `29 in adjusted position on meine ber `28. A ring 32 having graduations on its peripheral surface is secured on the periphery of the member 28 oi the outer slide and suitable refe erence marking is provided on the adjacent edge of the adjustable member 29 to cooperate with the graduations on member 32 and facilitate the adjustment of member `29 for purposes which will later be explained. A set screw 33 `serves to adjustably secure ring 32.

To effect the receding movements of the chaser A blocks 2l and chasers 22 a cam ring 34` is secured to the member 29 of the outer slide, by a retaining ring 35 and screws 36, so that the ring 3l!` slidably engages the inner surface of the member 28. To the ring-34 a plurality of cam blocks 3l are secured by screws 38, 39 in position to operatively engage the chaser blocks 2I, the chaser blocks and cam blocks being provided with interlocking tongue and groove cam surfacesin well known manner, which alsois disclosed in the above mentioned Patent 2,054Q028.` With the parts constructed as described, move-- ment of the cuter slide and the cam blocks 37 to the left serves to withdraw the chaser blocks outward to effect their receding movement to producen taper thread.

`.In addition to the springs, not shown but above referred to as interposed between theI head I9 and the chaser blocks :2I to urge the latter radiV gageth'e cylindrical interior surface of outer slide member 2E. 'Ihe slide member lI2 is formed with an `axial bore within which is mounted a work engaging structure 43 which comprises 'a work'- engaging pressure pad 43a detachably secured to the main body of `structure-413 by screw 431). The structure 43 is urged to the right in relation to the inner slide member 42 by a coil .spring 44 but such ymovement to the right is limited by miti t5 the left end of structure 43. Movement ofthe structure 133 toward the left in relation tol member 42 is limited by engagement of shoulder 43o with anopposing shoulder ionsmembendh The slide member 46 is slidably supported in a cylindrical abutment block- 48 which itself fits slidably in the bore of spindle I I but is normally secured against sliding movement therein by means which will later be described. 49 is a cam barpivotally mounted at its right end on a pin U carried by slide member 46 (Figs. 7 and 17). A t its left end cam 49 carries a depending pin 5I which engages the cam slot of a cam 52 mounted in member 46 for a guided sliding movement parallel to the axis of the die. Cam block 52Vis adjustably connected by screw 53 to slide member 46. By inserting a screw driver or other suitable tool in the left end of the die, screw 53 mounted and guided in the abutment 48 for movement at right angles to the die axis. This cam member V54 has a depending pin which engages a slide block 56 in the cam groove of cam block 49 (Fig. 18), so that the movement oircam 49Vwith the inner slide eiects transverse movement of cam 54. Cam 54 is formed with a tongue 54a which in turn engages a cam groove 51a in the transverse bar 51 which is Vsecured to the left end of the Iouter slide structure by means of screws 58, 58.

By means ofthe several cam members last described, one of which (54), it will be recalled, is anchored in the abutment member 48, longitudinal movement of the inner slide structure 4I is transmitted on a reduced scale to the outer slide structure 25 while the movement of the latter is in turn transmitted through a further rey duction to the chaser blocks 2 I Provision is thus made for the relatively small receding movement of the chasers which is effected during the threading operation in the cutting of taper threads. By adjusting the cam block 49 on its pivot, as above described, the degree of taper of the thread cut can be varied from a maximum corresponding to the adjustment shown in Fig. 13 to the minimum of the adjustment shown in Fig. 14 where the movement transmitted by cam 49 is nil and a straight thread is cut.

A flanged sleeve 59 is secured by screws 6U in the left end of spindle body II and the right end of this sleeve serves as a stop limiting movement toward the left of Vabutment 48. Pressure tending to move said abutment toward the left is constantly exerted upon it by a pair of coil springs 6I, 6I (Fig. 12) which are interposed between the abutment and ange 42a, of the inner slide member 42. These springs are supported on rods 62, 62 which are secured to the ange 42a and slidably engage the abutment 48. At their, left ends the rods 62 carryV pistons 63. which serve with the cylindrical chambers in rwhich they. work.. as air dash-Pots.

diametrically opposite spring mounted latchesV 64', 64 which have bevelled outer ends engaging a latch groove 59a in the sleeve 59. Normally these latches are positively held in locking engagement with sleeve 59 by means of a detent member in the form of sleeve 65 which is formed With a collar 65a that is perpherally atted at diametrically opposite points to engage the nat inner ends of the latches, as shown in Fig. 8. The sleeve 65 is yieldingly pressed toward the right byvcoil spring 66 which is interposed between the collar 65a of the sleeve and a circular plate or disc 61 which is removably secured to the left end of abutment 48. The Walls of sleeve 65 are formed with diametrically opposite slots 65h through which extends a transverse pin 68 the two ends of which are anchored in notches in the annular central boss of the end plate 61 of abutment 48. The purpose of the pin will presently appear.

At its left end the detent sleeve 55 is circumferentially grooved to cooperate with the end of a manually operated lever 69 by means of which sleeve 65 can be shifted to the left against the tension of spring 66, in order to release the latches 64 so that the pressure of the abutment 48 under the urging of springs 6l will cause the disengagement of the latches and permit the abutment to move toward the left inthe spindle body I I When such movement, which is rapid,

, occurs the pistons 63 cushion the movement and prevent undue shock.

A rod or spindle 10 is disposed within the sleeve S5 for longitudinal movement therein, the rod having direct sliding engagement with the sleeve at its left end and having its enlarged-right end fitted with a sleeve 1I which slidably engages the right end of sleeve 65. The transverse pin 68 extends through an elongated slot 16d4 in the rod 1I] so that the latter can move endwise without interference with the pin. rIhe rod 19 is normally urged toward the right by coil spring 12 which at one end engages the large right end of rod 1I) and at its other end engages the pin 68, the latter thus serving as an abutment for the spring.

An elongated rod 13 is slidably mounted in the abutment 48 and is disposed parallel to the axis of the die with its left end engaging the right end of rod 10 and with its other end engaging the nut 45 of the work engaging slide member 43 so as to transmit movement toward the left of member 43 to rod 1I). At its left end the rod or spindle 10 is fitted with a pair of ball bearings` 14 upon which is rotatably mounted a cylindrical cam 15. This cam is arranged to cooperate with a lever 16 pivotally mounted on a block 11 which is itself slidably mounted on a bracket 18 secured to the main frame of the machine.

A coil spring 19 interposed between the bracketY 18 and the block 11 urges said block toward the right. At its right end the block is fitted with an anti-friction roller 11a disposed to engage the end plate 610i abutment 48. The lever 16 is fitted at its free end with an anti-friction roller to engage the cam 15 and on its upper side the lever 16 is arranged to operatively engage an anti-friction roller carried by operating leve'r 8| of a compressed air pilot valve 80. The purpose of the air valve will later appear.

. Variable speed drive gear for die spindle I The variable speed spindle drive mechanismY designated aseentilety by 1 ,wmpriee the..

9 driven gear I5 `fast on the die spindle body The gear I5 is driven from the `motor 6 by a train of gears which comprises a shaft 82 rotatably mounted on the main frame ofthe machine and driven by means of belts 83 from the motor. A bevelled pinion 84 fast on shaft 82 meshes with a bevelled gear 85 on shaft 8B. Spur gears 81 and B8 are rotatably mounted on shaft 86 and are provided with clutch teeth to ycooperate with a sliding clutch member 89 splined on the shaft. The gears 81 and imesh with gears l9|) and9l, respectively, fast on counter shaft 92 andi gear 90 in turn meshes with the driven gear I5 on the die spindle. As shown in Figs. 2 and, thesliding clutch member 89 can be manually shifted by means of a lever 89a mounted on shaft iibywhich shaft can be manually actuated by hand lever 89e which turns shaft 89d on which is mounted lever89e which in turn is connected by link 89j with a lever arm 89g on shaft 89h. By shifting the hand lever 89e the die spindle can be driven at either of two speeds for. a given motor speed.

Variable s'peed drive gear for carriageV feed mechanism The variablespeed drive mechanism designated as an entirety by the numeral-8 and which is operatively interposed' between the die `spindle and the carriage feedmechanism 5, comprises an 'elongated main shaft 93 which extends practically from endto end of the machine with bearing supports in themain frame thereof. A second shaft 94 (Fig. 6) has a sleeve 95 rotatably mounted thereon with a spur gear 96 keyed to the sleeve and inr mesh with driving gear IB fast on thespindle body of the die. Thesleeve` 95 comprises a pinion 91 and an adjacent spur gear 93 is keyed on shaft 94. Spurgear 99 and pinion are keyed on counter shaft I 0| and mesh, respectively, with pinion 91 and gear 98. Shaft 94 is thus driven from spindle body I with a double speed reduction.

Shaft 94 carries a pinion |02 at its left end which drives a gear` |03 fast 4on shaft. |04 and a gear also fast on `shaft |04 drives gear` |06 fast on the main shaft 93 through an idler gear unit consisting of a pair of gears |91 and 08` and a splined supporting sleeve |09, the gear |01 being removable from the sleeve to permit substitution of a gear of different diameter. `To permit such substitution the idler gear sleeve |09 is mounted on a stub shaft I|0a carried by an adjustably mounted arm lill.. This arm is mounted to swing about the axis of gear |06 and can be locked by clampingscrew H971 in. differ ent positions to accommodate gears |91 of different diameters. Thus a. speed change can be made bymerely changing one gear and adjusting the position of arm I0;

Work carriage The work-feeding carriage 3 of the machine comprises a frame structure III which is` fitted with siide strips II2 of metal suitable forbearing engagement with ways Ib, Ib formed on the main` frame-of thermachine (Figs. 21 and 22). One of the slide strips ||2 isprovided with an adjustable gib |2a by adjustment ot` which compensation can be made for wear. lThe carriage frame III is provided at its righ-telde with a bolted-on extension |I3 which is provided with a removable cover plate |I3a which aii'ords access `to yparts whichwill presently be described.

Carriage feed and retractiondem'cee The carriage. 3\.is iedforwardltoward the die 2 .and retracted therefrom by mechanism comprising a .cam |I4 having a straight elongated cam groove ||4a and mounted upon a carrierin the form of a cylinder block |I5 which in turn'is slidably mounted in the main frame extension Ia to reciprocate transversely ofthe machine (Figs. 4, 23, 24, 25). The cam plate ||4 is pivotallyi attached to the block ||5 by a pivot pin IIB (Fig. 23) and by clamping screws ||1, II1 which pass through slots in the plate and permit its angular adjustment. To effect such adjustment a screw I|8 is provided (Fig. 5) which is rotatably mounted on the block I I5 and actuates a nut IIa that operatively engages cam plate ||4 to move it baci: andforth as the screw is turned. Cam plate ||4 drives a follower block H9 which is adjustably secured to the carriage extension ||3 by means of a clamping nut. The carriage extension 3 carries a notched plate I2| and` the cam block is formed `with teeth |"|9`a to engage the notches of such plate, thus `providing six diiferent positions of adjustment corresponding to the six notches of plate |2I. The block ||9 has a depending cylindrical. lug ||9b which fits an aperture in a block ||9c that slidably engages the cam groove |4a. The block ||5 is formed with a cylinder |22 having a front cylinder head |23 and a rear head |241. Operatively mounted in the cylinder |22 of the slidable block I5 is a piston |25 having a hollow rod |26 which extends through a stuiiing boX in the `head |24 and at its rear end is secured toa bracket |23` bolted to the frame extension Ia, so that in operation block ||5 reciprocates in relation to the fixed piston. Adjacent the piston the rod |2|ihas asmall hole |21 through which the bore of the rod communicates with the interior of the cylinder |22. The front head |23 of the cyl'- inder is fitted with a restricted air hole |23a.

The cylinder block ||5 has rigidly attached to it an elongated rack |29 which is arranged to be actuated by pinion |30 keyed on a jaw clutch member I3 I which is rotatably mounted on shaft |32 having rotatable bearing support intheframe extensionV la, (Fig. 23). A second clutch-mem- -ber |33 is slidably splined on shaft |32 t0 engage and drive the clutch member |3|, a shift lever |34 for the clutch member |33 being mounted on a pivot pin |35 carried by frame extension Ia (Fig. 25). Shaft |32V also` carries a drive gear |35 which isdriven from gear |31 on shaft 93 through an intermediate gear |33 (Fig. 4i).

It will be seen that the work carriage ofthe machine is. advanced toward the die by reciprocation of the cam plate ||4 toward the front of the machine and is withdrawn from the die by the reverse movement. The forward feed movement is designed to `be' effected at relatively low speed by closing the clutch |33 so that the cylinder block |I5 and cam plate ||4 are driven from the die spindle by means of the-rack and gear and other elements of the train of gearing bem tween the cylinder -block and the die spindle. The reverse movement `of the cam plate ||4, on the other hand, is effected at relatively high speed by disengaging the clutch I 33 andfadmitting pressure fluid through the hollow piston rod |26 into thecylinder |22 so as to effect the return movement of the cylinder block and the cam plate thereon. i

Manual operation of the carriage At times it is desirable to move thework carriagemanually and to that end the carriage frame |I| is fitted with a rack |39, and a pinion |40 mountedon a transverse shaft |4|` rotatably sup- Vmounted in frame ported in the frame I. of the machine meshes with the rack so that the carriageV can be moved on its supporting ways by rotation of the Shaft. Such rotation maybe effected manually by applying a hand bar |42 to a capstan |4| a on the shaft (Figs. 1,'20, 22). To permit of the manual actuation of the carriage it is necessary to break the drive connection between the carriage and the cam plate l||4 and to accomplish this the clamping nut |26 of the coupling block 9 between the carriage and the cam plate may be backed off to permit lowering of block H9 and the disengagement of' its teeth ||9a from the notches of plate |2|.

fThre work:` chuck. or gripper The work-holding gripper or chuck mechanism 4 is supported and more or less housed by the frame of carriage3. The mechanism as shown in Figs. 19-22, comprises a pair of opposed gripper blocks |43, |43 slidably mounted in the carriage frame I. Each of these blocks carries a gripper jaw |44 secured to the block by a single screw |45. To secure the accurate positioning of the jaw in relation to the block |43 and its rigid support thereon so that the jaw will always be held in proper alignment withthe axis of the threadforming die of the machine, the meeting faces of each `block |43 and its mating jaw |44 are transversely channeled in the manner indicated by Figs. 19 and 21, the channel in the block |43 extending horizontally while the channel in the jaw extends vertically. This channel formation of the two parts provides theblock |43 with flanges |43a which respectively overlap the top and bottom surfaces of jaw |44 (Fig. 21) while the channel of jaw |44 provides flanges |44a which overlap the vertical sides of block |43 (Fig. 19)

The gripper blocks |43 are actuated by vertically disposed levers I46, |46 which are pivotally mounted intermediate their ends on short shaft Aend of shaft |48 Vis rotatably mounted in a sleeve |50 which has a screw threaded engagement with the carriage frame I The flanged end of sleeve |50 is notched for engagement with a detent |5| adjustably mounted on frame In addition, the rear end of shaft |48 has fixed upon it a cylindrical sleeve |524 which is longitudinally grooved to cooperate with a spring detent |53 slidably By loosening thedetent |5| and rotating the sleeve |50 the pivotal supports of levers |46 can be shifted forward or rear- Ward in relation to the axis of the gripper jaws |44. Such adjustment is a matter of great convenience both in the original assembly of the gripper mechanism and later when the gib or gibs ||2a may be adjusted to compensate for wear after prolonged use.

The levers |46 are actuated by blocks |54 slidably mounted inframe these blocks being tted with short shaft sections |55 having cylindrical apertures in which the lower ends of levers |46 are operatively engaged, thus forming connections between the blocks and the levers like the connections between the upper ends of the levers and the gripper blocks |43. The blocks |54 in turn are driven by a toggle linkage comprising the `links |56, |56 which are in turn connected to block 51 slidably mounted to reciprocate in the frame on lines parallel to the axis of the machine (Figs. 19, 20). The block |51 is arranged to be actuated by a lever |58 pivotally mounted on the frame and operatively connected with block |51 by link |58a. The lever |58 is itself driven by a fluid pressure motor' |59 comprising a trunnion mounted cylinder |60 enclosing a piston with a rod |6| which is pivotally connected to the free end of lever |58. The motor cylinder may be connected with a source of compressed air or other Working fluid. It will be-seen that when the piston of motor |59 is moved forward toward the threading die the toggle linkage is straightened and the chuck jaws are moved toward each other to griprthe work, and on the reverse movement of the motor cylinder the chuck jaws are separated to release the work.

The work-supporting means To support the work piece and facilitate its engagement by the chuck jaws the carriage is provided with a pair of conical rollers |62 which are mounted upon slides |63 that engage Ways Ib on the frame A These slides carry trunnion yblocks |63a upon which the rollers are mounted with interposed ball bearings |64. To provide for adjustment of the rollers |62 toward and from each other a rod |65 is rotatably mounted in a bearing bracket |66 on frame and the rod is formed with screw threads engaging mating threads in the slides |63, one set of the threads being right hand and the other left hand so that rotation of the rod |65 in one direction moves the rollers |62 toward each other while its rotation in the opposite direction moves the rollers away from each other. The bearing bracket |66 is provided with a spring pressed detent |61 designed to engage depressions in the rod |65 to hold it in different adjusted positions.

Automatic chaser re-setting mechanism Following the rapid collapse of the chasers at the end of the thread-cutting operation caused by the release of the cam abutment block 46, it is necessary torestore the chasers and the various related parts of the mechanism including the inner and outer slide structure and the cam abutment block, to their respective positions oc cupied at the beginning of the thread-cutting operation. This restoration of the parts is usually referred to as re-setting.

In the machine illustrated the re-setting is automatically effected by devices which comprise a re-setting yoke |68 carried by a pivotal support |69 on the main frame in vertical alignment with the axis of the die. The upper ends of the yoke arms are fitted with anti-friction rollers |10 designed to engage the fiat annular surface of the outer slide head member 26 adjacent its periphery (Figs. 1, 28). The yoke carries a fixed pawl I1| designed to engage the notches of a ra-ck member |12 which is operatively connected to the carriage 3. This latter connection is effected through a short shaft section |13 rotatably mounted in the rack, a bolt |14 which slidably engages a hole in the shaft section |13 and a nut |15 operatively engaging the bolt and the carriage frame to adjustably connect the two parts. The connection of the rack |12 to the carriage also comprises a heavy coil spring |16 interposed between the shaft |13 and the head o; the bolt |14 and a relatively light coil spring arranca .13 |11..` interposed between: itheA Vshaft :|131arandwthe vcarriage frame. With'the chasers 'of thefdieset 'for a cutting .operationz and the-,carriage fully i retracted both of the Vsprings ls'land |11 should be under` some compression.

The notches of the rackz IlZLarethe` same in numberV and spacingas the: notches of. thecarriage plate |2| bywhichfthecam follower block |f|9 is adjustably connected with. thez. carriage. Thus. when an adjustment of' the' carriage and the Work gripper in relation tothe diewto anyone of six different positions is `eiectedby flxingthe position of the cam follower block ||9:,;the .piv otal connection of the rack |12 with the bolt |1l|l permitsthe lifting of the rack andthe engage-1 tion of the chasers needed for the `predetermined" VVtaper of thethreads beim;l cut. To insure that the outer slide `25 shall'. be free for such movement without interference from vthe re-setting yoke .|58 which is simultaneously moved by the carriage, the position .of the pivotal support ofy `the yoke in` relation toits connections with the rack `|12 andthe slide 25` of the dieis chosen ..such..that the rack will `move the anti-friction rollers `|10 of the yoke |88 more rapidly than `.the `outer slide 25 is` moved, even for a thread of `the .maximum taper. On the reverse movement of the carriage following rapid collapse of the chasersthe rack |12 is drawn to the right by the ,carriage and causes the re-setting yoke |58 to correspondingly move the outer slide 25 and re- .setthe chasers.

In its re-setting movement the outer slide 25 not.only restores. the chasersto their initial posi- .tion ready. for the next cutting operation, but also carries with it the inner slide structure and the. abutment 48. This follows from4 the fact that the train of cam connecting devices which transmit the movement of the inner, Work-enl gagingsIide tothe outer slide is non-overhauling and, through cam 54, is` anchoredin 4abut- V ment'v 48. Hence when the outerslide is moved" `by the re--setting yoke, the outer slide, cams. inner. slide and abutment move as a unit and return to their initial positions. As the abut- .ment moves intoits initial position its spring-y pressed latches 84 snap into locking engagementl Manual ehosercollapse and rra-setting devices It is-desirable at times, as. when the chasers are' to be inspected or changed, to draw the chasers Vradially apart to increase their accessibility and it. is'desirable to be able to do this Amanually. Accordingly the following-described devices are provided to efectithezmanual collapse and re-setting of the die.

Adjacent the; stem of the yoke |68 is a cam disc |18 rotatably supported by ashaft |118acari nected` by;` a.` pair ofslottedlinkselTS withtthe yokel|168 through blocks |88 lpivotally attached :to the yokenand havingL a slidingwengagement Awith the slots of thelinks, 4thus eiecting` alost motion connection between the` links :and the yoke. `The `cam disc |18 is also lconnectedfby-a link |81 with the previously describedqlever-Bl `the llink |8| having its rightend slottedtocooperate with a slide block |82-pivotally attached to the cam disc.

For manualy operation of the cam disc |18 a `hand lever |83 mounted onthe lfront .of the machina But' `for interference by shaft S31-the 4shaft IlliaV might be extended to thefront` ofV the `some Vlost motion between disc |18and link |18.|,

' tion between it. andthe links` |19;

:main frame ofisthe machine. y'rear `side ofrthe machine are a cam-actuated pilot machine and handlever |83 mounted upon it.

' To `avoid suchinterference the lever is mounted on .az shaft |83a. rotatably supported oir the frame and operatively connected to cam disc bythe frame I.

In'Fig. 28 the hand lever |83 is shownin-its normalposition and it'will be seen that by swinging: the leverzto the-left the cam disc |18 is rotated counter-clockwise This rotation, `after servesV to: move sleeve to the left, unlatch .the abutment block 48 and eiectthecollapse ofthe chasers, the .corresponding movement of theyoke lrbeing permitted by' the lost motion connec- To` permit the statedmovement of the cam disc |18. inde- `pendently ofthe work carriage the-peripheral cam surface of the disc is arranged to engagethe extendedrleft end ofzthe rack |-12land swingsitup- `wami on its pivotal connection with the'lbolt .|114 i' enoughlto disengage` itfrom the pawl |1|.-\ ofvthe y're-setting yoke.

This `action is shown in Fig. 30. When itis--desiredtov re-set the chaserssthe hand lever |83 is` moved to the right to and beyond its normal position,` as shown in lig.V 31. This `movement the cam disc` |18is turnedfto a posi- Ltion permitting the return of the rack. |12 Vinto engagement with the pawl |1| thus restoring .the vconnection between. the carriage` and the` yoke |68. The-handilever may then-be restored toits "normal position shown'in Fig. 28. `In restoring f the: connection of the pawl |:1l .with the rack |12 the-.engagement of the pawl` in the `correct-notch oi' theirackfis'insured by the action ofspring |11.

i Fluid pressure control devices tion to be engaged by the chasers and gripped by the chuck. The partsand devices involved in "such automatic control will now be described. `"Referring tothe rear elevation shown in Fign26 .65.

and-thediagram shown in Fig. 32, |81 istarcompressed air supply pipe which is connected through a. l manual` cut-olf valve` 188i withsome vsuitable v source of compressed air. Suchta source'may` be amotor-.driven compressor mountedrupon the Mounted on the valve |89,1pressureoperated valves |88 and |`9| and a cam-operated-valve |82.` Similarly mounted ,is a compressed air motor |93` having aetrunnion cylinder |8'4,;:pistonf|,85 and pistonirod-` |98xex- 

